sdk/2.1/docs/man/clGetDeviceAndHostTimer.xml

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<!ENTITY cl_device_type_Inc SYSTEM "cl_device_type_Inc.xml">
]>

<refentry>
    <refentryinfo>
        <keywordset><keyword>clGetDeviceAndHostTimer</keyword></keywordset>
    </refentryinfo>
    <refmeta>
        <refentrytitle>clGetDeviceAndHostTimer</refentrytitle>
        <refmiscinfo>
            <copyright>
                <year>2007-2013</year>
                <holder>The Khronos Group Inc.
 Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and/or associated documentation files (the
"Materials"), to deal in the Materials without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Materials, and to
permit persons to whom the Materials are furnished to do so, subject to
the condition that this copyright notice and permission notice shall be included
in all copies or substantial portions of the Materials.</holder>
            </copyright>
        </refmiscinfo>
        <manvolnum>3</manvolnum>
    </refmeta>

<!-- ================================ SYNOPSIS -->

  <refnamediv id="clGetDeviceAndHostTimer">
    <refname>clGetDeviceAndHostTimer</refname>
    <refpurpose>Returns a reasonably synchronized pair of timestamps from the device timer and the host timer as seen by device.</refpurpose>
    </refnamediv>
    <refsynopsisdiv xmlns:xlink="http://www.w3.org/1999/xlink"><title></title>
        <funcsynopsis>
            <funcprototype>
                <funcdef>
                    <link xlink:href="scalarDataTypes.html">cl_int</link>
                    <function>clGetDeviceAndHostTimer</function>
                </funcdef>

                <paramdef>
                    <link xlink:href="abstractDataTypes.html">cl_device_id</link>
                    <parameter>device</parameter>
                </paramdef>

                <paramdef>
                    <link xlink:href="scalarDataTypes.html">cl_ulong *</link>
                    <parameter>device_timestamp</parameter>
                </paramdef>

                <paramdef>
                    <link xlink:href="scalarDataTypes.html">cl_ulong *</link>
                    <parameter>host_timestamp</parameter>
                </paramdef>
           </funcprototype>
        </funcsynopsis>
    </refsynopsisdiv>

<!-- ================================ PARAMETERS -->

    <refsect1 id="parameters"><title>Parameters</title>
        <variablelist>
        <varlistentry>
            <term><varname>device</varname></term>
            <listitem>
                <para>
                    A device returned by 
                    <citerefentry><refentrytitle>clGetDeviceIDs</refentrytitle></citerefentry>.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><varname>device_timestamp</varname></term>
            <listitem>
                <para>
                    Will be updated with the value of the current timer in nanoseconds. The
                    resolution of the timer is the same as the device profiling timer returned by 
                    <citerefentry><refentrytitle>clGetDeviceInfo</refentrytitle></citerefentry> 
                    and the 
                    <constant>CL_DEVICE_PROFILING_TIMER_RESOLUTION</constant> query.
                </para>
            </listitem>
        </varlistentry>

        <varlistentry>
            <term><varname>host_timestamp</varname></term>
            <listitem>
                <para>
                    Will be updated with the value of the current timer in nanoseconds
                    at the closest possible point in time to that at which 
                    <varname>device_timer</varname> was returned. 
                    The resolution of the timer may be queried via 
                    <citerefentry><refentrytitle>clGetPlatformInfo</refentrytitle></citerefentry> 
                    and the flag
                    <constant>CL_PLATFORM_HOST_TIMER_RESOLUTION</constant>.
                </para>
            </listitem>
        </varlistentry>

        </variablelist>
    </refsect1>

<!-- ================================ NOTES  -->
    <refsect1 id="notes"><title>Notes</title>

    <para>
        Returns a reasonably synchronized pair of timestamps 
        from the device timer and the host timer
        as seen by <varname>device</varname>. Implementations 
        may need to execute this query with a high latency in order
        to provide reasonable synchronization of the 
        timestamps. The host timestamp and device
        timestamp returned by this function and 
        <citerefentry><refentrytitle>clGetHostTimer</refentrytitle></citerefentry> 
        each have an implementation defined
        timebase. The timestamps will always be in 
        their respective timebases regardless of which query
        function is used. The timestamp returned from 
        <citerefentry><refentrytitle>clGetEventProfilingInfo</refentrytitle></citerefentry> 
        for an event on a device
        and a device timestamp queried from the same 
        device will always be in the same timebase.
    </para>

    </refsect1>

<!-- ================================ ERRORS  -->

    <refsect1 id="errors"><title>Errors</title>
        <para>
            <function>clGetDeviceAndHostTimer</function> will return <errorname>CL_SUCCESS</errorname> 
            with a time value in <varname>host_timestamp</varname> if provided.
            Otherwise, it returns one of the following errors:
        </para>

        <itemizedlist mark="disc">
        <listitem>
            <errorname>CL_INVALID_DEVICE</errorname> if <varname>device</varname> is not
            a valid OpenCL device.
        </listitem>

        <listitem>
          <errorname>CL_INVALID_VALUE</errorname> if <varname>host_timestamp</varname> 
          or <varname>device_timestamp</varname> is NULL.
        </listitem>

        <listitem>
          <errorname>CL_OUT_OF_RESOURCES</errorname> if there is a failure to allocate resources
          required by the OpenCL implementation on the device.
        </listitem>

        <listitem>
          <errorname>CL_OUT_OF_HOST_MEMORY</errorname> if there is a failure to allocate
          resources required by the OpenCL implementation on the host.
        </listitem>

        </itemizedlist>
    </refsect1>

<!-- ================================ EXAMPLE  -->
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    <refsect2 id="example1">
        <title>
            Example
        </title>

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                <colspec colname="col1" colnum="1" />
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<!-- ================================ SPECIFICATION  -->
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    <refsect1 id="specification"><title>Specification</title>
        <para><imageobject><imagedata fileref="pdficon_small1.gif" format="gif" /></imageobject>
            <olink uri="clGetDeviceAndHostTimer">OpenCL Specification</olink>
        </para>
    </refsect1>

<!-- ================================ ALSO SEE  -->

    <refsect1 id="seealso"><title>Also see</title>
        <para>
            <citerefentry><refentrytitle>clGetHostTimer</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>clGetDeviceInfo</refentrytitle></citerefentry>,
            <citerefentry><refentrytitle>clGetPlatformInfo</refentrytitle></citerefentry>
        </para>
    </refsect1>

<!-- ============================== COPYRIGHT -->
<!-- Content included from copyright.inc.xsl -->

    <refsect3 id="Copyright"><title></title>
        <imageobject>
                <imagedata fileref="KhronosLogo.jpg" format="jpg" />
        </imageobject>
        <para />
    </refsect3>

<!-- 29-Oct-2015, API rev. 19 -->
</refentry>